Optical data transceiver modules convert optical signals received via an optical fiber into electrical signals and convert electrical signals into optical signals for transmission via an optical fiber. In the transmitter portion of a transceiver module, a light source such as a laser performs the electrical-to-optical signal conversion. In the receiver portion of the transceiver module, a light receiver such as a photodiode performs the optical-to-electrical signal conversion. A transceiver module commonly also includes optical elements, such as lenses, as well as electrical circuitry such as drivers and receivers. A transceiver module also includes one or more fiber ports to which an optical fiber cable is connected. The light source, light receiver, optical elements and electrical circuitry are mounted within a module housing. The one or more fiber ports are located on the module housing.
Various transceiver module configurations are known. One type of transceiver module configuration is known as a mid-plane mounting configuration. A transceiver module having a mid-plane mounting configuration commonly has a module housing with a generally square base and a low height. The base or bottom of the module housing has an array of electrical contacts, such as a Ball Grid Array (BGA), on its lower surface. A fiber port is located on the upper portion or top of the module housing. In some transceiver modules, the fiber port can be connected to an optical ribbon cable ferrule or connector. The optical ribbon cable connector thus terminates and retains the end of an optical ribbon cable comprising multiple optical fibers. The optical ribbon cable connector can have a plug-like shape that is mechanically received in a mating region of the fiber port. When the optical ribbon cable connector is received in or retained in the transceiver module fiber port, optical ports of the optical ribbon cable connector are aligned along optical paths with corresponding optical ports of the transceiver module fiber port. Thus, when the optical ribbon cable connector is received in or retained in the transceiver module fiber port, optical signals can be communicated along these optical paths between the optical ribbon cable connector and the transceiver module fiber port.
An optical ribbon cable connector can include reflective surfaces that redirect or “turn” optical signals between the ends of the fibers and the above-referenced optical paths. Such a connector may be referred to as a reflecting connector or optical-turn connector. The optical paths between a reflecting connector and a transceiver module are commonly perpendicular to the optical axes of the ends of the fibers retained in the reflecting connector. Thus, an optical signal emitted from the end of a fiber is reflected at an angle of 90 degrees through a corresponding optical port of the reflecting connector and into the transceiver module fiber port. Similarly, an optical signal emitted from the transceiver module fiber port is reflected at an angle of 90 degrees into a corresponding optical port of the reflecting connector and into the end of a fiber. The optical ports of the reflecting connector through which the optical signals are communicated are located on the lower portion of the reflecting connector. A pair of alignment pins commonly extends from the lower portion of a reflecting connector.
It is known to provide a cover that fits over the upper portion of a reflecting connector. The upper portion of the cover protects the reflective surfaces against contamination by dust or other foreign matter that could impair the reflectivity. The lower portion of the cover includes latching projections or ears. The latching ears have openings that are configured to engage protuberances on the module housing. As the cover-and-connector assembly is lowered onto the module, the alignment pins of the reflecting connector are received in corresponding bores in the module housing, and the latching ears of the cover snap onto the protuberances on the module housing to retain the cover and thus the reflecting connector in place on the transceiver module.
Although the above-described latching procedure may seem straightforward, in actuality a user may find it difficult to align the cover with the module and snap the cover into place due to the relatively small size of the module (e.g., commonly on the order of 20 mm on each side of the base of the module housing) and accordingly small size of the cover-and-connector assembly. The alignment pins are correspondingly small and easily damaged if forced against a surface. Also, due to the latching ears extending beyond the lower portion of the reflecting connector, the cover-and-connector assembly has a relatively high profile.